Need advice: vibration Kenworth T680

Time to get dirty and crawl under your truck. Motor mounts, bell housing mounts, u-joints, ride height, drive line angle, loose yolks, torque arm bushings, on and on.

 

Get a good flashlight. Get under the truck between the back end of the fuel tank and the drive tires (unless you're one of these super skinny wet noodle sorts.. I know getting under a T680 without lifting it can be a real ############ for me if I try going under the tanks)... check the aforementioned, and also take a good look at your wheel seals while you're at it... we've had an epidemic of those going out on the 680s.
If you don't already have a long-handled 1/2" drive ratchet and a short extension, get one... we've had a couple cases of transmission oil leaks developing on the newer 660s and 680s. It would also help to have a 5/8" 8 point socket (or a 5/8" combination wrench will suffice) because they tend to come from the factory with way too much oil in the diffs.
If you have a torque wrench, check your air bags.. torque the bolts under the air bags to 50 ft/lbs. (they're substantially less than this from the factory).
And most of our 680s have come to us with a little bit of toe out... you'll want to adjust that... ideally, we go for 1/16" toe-in, but anything less than 1/8", we roll with.

 

had the same issue,transmission yolk replaced problem solved.

 

Start with the simple things, tire pressure and grease the 5th wheel.

 

So you really think the tech at the dealer is going to check everything perfectly under your truck?

 

What engine do you have?? Is the ride height correct? How many km's on it?

 

Also check your clutch adjustment. Ours have been coming from the dealership out of whack, but it can be easy to miss on account of the hydraulic clutch (IMO, a ####### stupid idea for trucks, but the geniuses who figured out lights and power windows need to be run through the ECM disagree, so who am I to argue?).

 

Ride Height is very important because it changes the length the driveshaft on the yoke. Gas shocks helped with my first T680 as well. The model with the air ride with the shocks mounted on the inside of the frame seems to ride better in general as well.